Assessing the contribution of road transport emission to air pollution and greenhouse gases in Africa: A disaggregate study in Kenya

Air pollution and greenhouse gas emissions affect health, climate and agriculture. In sub-Saharan Africa (SSA) air quality monitoring is underdeveloped which leads to uncertainty in the understanding of air pollution concentrations. However, studies that have been conducted in SSA show that ambient air pollution generally exceeds World Health Organization (WHO) guidelines. These studies show particularly high concentrations in urban areas such as Nairobi, Kenya. One of the key reasons is due to emissions from transport. Therefore, the main objective of this thesis is to quantify transport related emissions, set within the context of emissions from other sectors, using Nairobi, Kenya as a case study. Thus, this thesis has developed a methodology and framework at different scales (individual vehicle, city and national) to improve our understanding of transport-related emissions of air pollutants and greenhouse gas (GHG) to help guide policy making on future mitigation plans.
Road transport emissions were investigated at multiple scales; at the finest scale, particulate matter (PM) emissions from the tailpipe were measured for a few vehicles using a novel multiplexed portable measurement system. At the urban scale, a model for fuel economy was constructed for a fleet from data collected in the field. Finally, at the national scale, available data gathered on fuel economy, vehicle activity and emissions were integrated to provide a country-level assessment of air pollution and GHG emissions from road transport, including evaluation of transport policies to reduce air pollution and GHGs.